I'm 29 in dior 19cm, what size should I buy for petit standards and new cure jeans.

Personally, I wear Dior 19cms in a size 27. My PS is a 26 and I recently sold my 26 NC because I felt they were slightly too tight. Note that I was able to try Diors in size 26, 28 and PSs in size 25 so I feel like I've found a good sizing in both brands for myself.